Differential Diagnosis for Right Sided Abdominal Pain

Given the history of appendectomy and a negative urine pregnancy test, the following differential diagnoses are considered:

• Single Most Likely Diagnosis

  • Cholecystitis: This condition, involving inflammation of the gallbladder, often presents with right upper quadrant abdominal pain, especially after eating fatty foods. The pain can sometimes be more generalized to the right side. Given the patient's history of appendectomy, which rules out appendicitis as a cause for right lower quadrant pain, cholecystitis becomes a more likely consideration for right-sided abdominal pain.

• Other Likely Diagnoses

  • Kidney Stone (Nephrolithiasis): Pain from a kidney stone can be severe and typically starts in the flank, then moves down towards the groin. It's possible for the pain to be felt on the right side if the stone is in the right ureter.
  • Pyelonephritis: An infection of the kidney, which can cause flank pain, fever, and other urinary symptoms. The pain can be on one side if one kidney is more affected than the other.
  • Hernia: Although less common, a hernia in the right abdominal wall could cause localized pain, especially if it becomes incarcerated or strangulated.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic abdominal pain, including on the right side, especially if the terminal ileum is involved.

• Do Not Miss Diagnoses

  • Ectopic Pregnancy: Although the urine pregnancy test is negative, it's crucial to consider ectopic pregnancy, especially if the test was done very early in the pregnancy. A negative test does not completely rule out pregnancy, especially if the patient has a history of irregular periods or if the test was performed too early.
  • Ovarian Torsion: This is a gynecological emergency that can cause severe, sudden onset of pain, usually on one side. It requires immediate surgical intervention.
  • Ruptured Ovarian Cyst: Can cause sudden, severe pain, usually on one side, and may lead to significant internal bleeding.
  • Diverticulitis: Although more common on the left, diverticulitis (inflammation of a diverticulum in the digestive tract) can occur on the right side and cause significant pain and potentially life-threatening complications if not treated.

• Rare Diagnoses

  • Intussusception: A condition where a part of the intestine slides into an adjacent part, potentially causing bowel obstruction. It's more common in children but can occur in adults, often with a lead point such as a tumor.
  • Mesenteric Ischemia: A condition where there's insufficient blood flow to the intestine, which can cause severe abdominal pain. It's more common in older adults or those with significant vascular disease.
  • Right-sided diverticulitis of the colon: While diverticulitis is more common on the left side, it can occur on the right, especially in individuals of Asian descent.